docs: def on_dummies(self, *args):
          """Give the dummies numbers such that, when appended to their names,
          they give a unique name for the resulting new
          :class:`board.Pawn` or :class:`board.Spot`.
  
          """
          def renum_dummy(dummy, *args):
              dummy.num = dummynum(self.app.character, dummy.prefix) + 1
  
          for dummy in self.dummies:
              if dummy is None or hasattr(dummy, '_numbered'):
                  continue
              if dummy == self.dummything:
                  self.app.pawncfg.bind(imgpaths=self._propagate_thing_paths)
              if dummy == self.dummyplace:
                  self.app.spotcfg.bind(imgpaths=self._propagate_place_paths)
              dummy.num = dummynum(self.app.character, dummy.prefix) + 1
              Logger.debug("MainScreen: dummy #{}".format(dummy.num))
              dummy.bind(prefix=partial(renum_dummy, dummy))
              dummy._numbered = True